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loxilb-io/loxilb#675 Initial support for proxy protocol v2
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@TrekkieCoder
TrekkieCoder committed Nov 27, 2024
1 parent 85c2f86 commit 38319bc
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Showing 4 changed files with 87 additions and 21 deletions.
12 changes: 11 additions & 1 deletion common/parsing_helpers.h
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Original file line number Diff line number Diff line change
Expand Up @@ -178,7 +178,17 @@ static inline int ipv6_addr_is_multicast(const struct in6_addr *addr)
static __always_inline __be16
csum_fold_helper(__be32 csum)
{
return ~((csum & 0xffff) + (csum >> 16));
csum = (csum & 0xffff) + (csum >> 16);
csum = (csum & 0xffff) + (csum >> 16);
return (__u16)~csum;
}

static __always_inline __be16
csum_fold_helper_diff(__be32 csum)
{
csum = (csum & 0xffff) + (csum >> 16);
csum = (csum & 0xffff) + (csum >> 16);
return (__u16)csum;
}

static __always_inline void
Expand Down
92 changes: 74 additions & 18 deletions kernel/llb_kern_cdefs.h
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Original file line number Diff line number Diff line change
Expand Up @@ -770,7 +770,7 @@ do { \
#define RECPP_LATENCY(ctx, xf)
#endif

#define RETURN_TO_MP_OUT() \
#define RETURN_TO_MP_OUT(ctx) \
do { \
xf->pm.phit |= LLB_DP_RES_HIT; \
bpf_tail_call(ctx, &pgm_tbl, LLB_DP_CT_PGM_ID);\
Expand Down Expand Up @@ -955,9 +955,10 @@ dp_rewire_port(void *tbl, struct xfi *xf)
}

static int __always_inline
dp_populate_ppv2(void *md, struct xfi *xf, void *start)
dp_populate_ppv2(void *md, struct xfi *xf, void *start, __be32 *csum)
{
struct proxy_hdr_v2 *ppv2h;
struct proxy_ipv4_hdr *piph;
__u8 sig[12] = { 0x0D, 0x0A, 0x0D, 0x0A, 0x00, 0x0D,
0x0A, 0x51, 0x55, 0x49, 0x54, 0x0A };
void *dend = DP_TC_PTR(DP_PDATA_END(md));
Expand All @@ -967,21 +968,25 @@ dp_populate_ppv2(void *md, struct xfi *xf, void *start)
LLBS_PPLN_DROPC(xf, LLB_PIPE_RC_PLERR);
return -1;
}

memcpy(ppv2h->sig, sig, 12);
ppv2h->ver_cmd = 0x21;
ppv2h->family = 0x11;
ppv2h->len = bpf_htons(sizeof(struct proxy_ipv4_hdr));

struct proxy_ipv4_hdr *piph = (void *)(ppv2h + 1);
piph = (void *)(ppv2h + 1);
if (piph + 1 > dend) {
LLBS_PPLN_DROPC(xf, LLB_PIPE_RC_PLERR);
return -1;
}

piph->src_addr = xf->l34m.saddr[0];
piph->dst_addr = xf->l34m.daddr[0];
piph->src_port = xf->l34m.source;
piph->dst_port = xf->l34m.dest;

*csum = bpf_csum_diff((__be32 *)ppv2h, sizeof(*ppv2h) + sizeof(*piph), 0, 0, *csum);

return 0;
}

Expand All @@ -990,6 +995,9 @@ dp_fixup_ppv2(void *md, struct xfi *xf)
{
struct tcphdr *tcp;
void *dend;
__be32 oval = 0;
__u32 nval = 0;
__u32 csum = 0;

if (xf->l2m.dl_type != bpf_htons(ETH_P_IP) || xf->l34m.nw_proto != IPPROTO_TCP) {
return 0;
Expand All @@ -1003,24 +1011,36 @@ dp_fixup_ppv2(void *md, struct xfi *xf)
}

if (xf->pm.oppv2) {
__u32 seq = bpf_ntohl(tcp->seq);
seq += sizeof(struct proxy_hdr_v2) + sizeof(struct proxy_ipv4_hdr);
tcp->seq = bpf_htonl(seq);
oval = tcp->seq;
nval = bpf_ntohl(tcp->seq) + sizeof(struct proxy_hdr_v2) + sizeof(struct proxy_ipv4_hdr);
tcp->seq = bpf_htonl(nval);
nval = tcp->seq;
} else if (xf->pm.ippv2) {
__u32 ack = bpf_ntohl(tcp->ack_seq);
ack -= sizeof(struct proxy_hdr_v2) + sizeof(struct proxy_ipv4_hdr);
tcp->ack_seq = bpf_htonl(ack);
oval = tcp->ack_seq;
nval = bpf_ntohl(tcp->ack_seq) - (sizeof(struct proxy_hdr_v2) + sizeof(struct proxy_ipv4_hdr));
tcp->ack_seq = bpf_htonl(nval);
nval = tcp->ack_seq;
}

csum = bpf_csum_diff((__be32 *)&nval, 4, (__be32 *)&oval, 4, tcp->check);
tcp->check = csum_fold_helper_diff((__u32)csum);

return 0;
}

static int __always_inline
dp_ins_ppv2(void *md, struct xfi *xf)
{
struct proxy_hdr_v2 *ppv2h;
struct iphdr *iph;
struct tcphdr *tcp;
struct tcphdr *ntcp;
void *dend;
struct proxy_hdr_v2 *ppv2h;
__u16 doff;
__u32 olp;
__u32 nlp;
__u64 flags;
__u32 csum = 0;

int len = sizeof(struct proxy_hdr_v2);

Expand Down Expand Up @@ -1049,18 +1069,25 @@ dp_ins_ppv2(void *md, struct xfi *xf)
return -1;
}

iph->tot_len = bpf_htons(xf->pm.l3_len + len);
iph->tot_len = bpf_htons(xf->pm.l3_len + len);
dp_ipv4_new_csum((void *)iph);

struct tcphdr *tcp = DP_ADD_PTR(DP_PDATA(md), xf->pm.l4_off + len);
dend = DP_TC_PTR(DP_PDATA_END(md));
tcp = DP_ADD_PTR(DP_PDATA(md), xf->pm.l4_off + len);
if (tcp + 1 > dend) {
LLBS_PPLN_DROPC(xf, LLB_PIPE_RC_PLERR);
return -1;
}

__u16 doff = tcp->doff << 2;
doff = tcp->doff << 2;

/* Checksum changes due to TCP segment length change */
olp = (__u32)bpf_htons(xf->pm.l3_plen);
nlp = (__u32)bpf_htons(xf->pm.l3_plen + len);
csum = bpf_csum_diff((__be32 *)&nlp, 4, (__be32 *)&olp, 4, tcp->check);

struct tcphdr *ntcp = DP_ADD_PTR(DP_PDATA(md), xf->pm.l4_off);

ntcp = DP_ADD_PTR(DP_PDATA(md), xf->pm.l4_off);
if (ntcp + 1 > dend) {
LLBS_PPLN_DROPC(xf, LLB_PIPE_RC_PLERR);
return -1;
Expand All @@ -1081,7 +1108,7 @@ dp_ins_ppv2(void *md, struct xfi *xf)
}
memcpy(ntop, top, 4);
ppv2h = (void *)(ntop + 4);
dp_populate_ppv2(md, xf, ppv2h);
dp_populate_ppv2(md, xf, ppv2h, &csum);
} else if (doff == 28) {
__u8 *top = (void *)(tcp + 1);
if (top + 8 > dend) {
Expand All @@ -1095,7 +1122,7 @@ dp_ins_ppv2(void *md, struct xfi *xf)
}
memcpy(ntop, top, 8);
ppv2h = (void *)(ntop + 8);
dp_populate_ppv2(md, xf, ppv2h);
dp_populate_ppv2(md, xf, ppv2h, &csum);
} else if (doff == 32) {
__u8 *top = (void *)(tcp + 1);
if (top + 12 > dend) {
Expand All @@ -1109,11 +1136,40 @@ dp_ins_ppv2(void *md, struct xfi *xf)
}
memcpy(ntop, top, 12);
ppv2h = (void *)(ntop + 12);
dp_populate_ppv2(md, xf, ppv2h);
dp_populate_ppv2(md, xf, ppv2h, &csum);
} else if (doff == 36) {
__u8 *top = (void *)(tcp + 1);
if (top + 16 > dend) {
LLBS_PPLN_DROPC(xf, LLB_PIPE_RC_PLERR);
return -1;
}
__u8 *ntop = (void *)(ntcp + 1);
if (ntop + 16 > dend) {
LLBS_PPLN_DROPC(xf, LLB_PIPE_RC_PLERR);
return -1;
}
memcpy(ntop, top, 16);
ppv2h = (void *)(ntop + 16);
dp_populate_ppv2(md, xf, ppv2h, &csum);
} else if (doff != 20) {
LLBS_PPLN_DROPC(xf, LLB_PIPE_RC_PLERR);
return -1;
}

dend = DP_TC_PTR(DP_PDATA_END(md));
iph = DP_ADD_PTR(DP_PDATA(md), xf->pm.l3_off);
if (iph + 1 > dend) {
LLBS_PPLN_DROPC(xf, LLB_PIPE_RC_PLERR);
return -1;
}

tcp = DP_ADD_PTR(DP_PDATA(md), xf->pm.l4_off);
if (tcp + 1 > dend) {
LLBS_PPLN_DROPC(xf, LLB_PIPE_RC_PLERR);
return -1;
}

tcp->check = csum_fold_helper_diff((__u32)csum);
}
return 0;
}
Expand Down Expand Up @@ -2128,7 +2184,7 @@ dp_llb_add_crc_off(void *md, struct xfi *xf, int val)
#define dp_sunp_tcall(x, y)
#define TCALL_CRC1()
#define TCALL_CRC2()
#define RETURN_TO_MP_OUT()
#define RETURN_TO_MP_OUT(x)
#define TRACER_CALL(ctx, xf)
#define RECPP_LATENCY(ctx, xf)
#define DP_SET_STARTS(xf)
Expand Down
2 changes: 1 addition & 1 deletion kernel/llb_kern_compose.c
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Original file line number Diff line number Diff line change
Expand Up @@ -992,7 +992,7 @@ dp_unparse_packet_always_slow(void *ctx, struct xfi *xf)

xf->pm.nf = 0;

RETURN_TO_MP_OUT();
RETURN_TO_MP_OUT(ctx);

return DP_DROP;
}
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2 changes: 1 addition & 1 deletion kernel/llb_kern_sum.c
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Original file line number Diff line number Diff line change
Expand Up @@ -99,7 +99,7 @@ dp_sctp_csum(void *ctx, struct xfi *xf)
DP_LLB_SET_CRC_OFF(ctx, (sctp_csum_off<<16));
}

RETURN_TO_MP_OUT();
RETURN_TO_MP_OUT(ctx);
}

/* Update state-variables */
Expand Down

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